Ammunition priming mixture



United States ANIMUNITION PRIMING MIXTURE No Drawing. Application May 24, 1954, Serial No. 432,053

5 Claims. (Cl. 52-4) This invention relates to a novel composition of matter, and to the use of such composition as an ingredient of deflagrating compositions, particularly ammunition priming mixtures.

This application is a continuation-in-part of my copending application, Serial Number 197,179, filed November 22, 1950, now Patent No. 2,689,788, issued September 21, 1954.

The conventional ammunition priming mixture comprises an oxygen-yielding substance or oxidizer, an oxygen-deficient substance or fuel adapted to combine with oxygen supplied by the oxidizer with the evolution of substantial heat and flame, a percussion-sensitive ingredient adapted to decompose under impact, and an explosive activated by and in conjunction with the percussion-sensitive material, generating suflicient heat and pressure to initiate the reaction between fuel and oxidizer.

Mixtures for rimfire cartridges usually contain, in addition to the above reacting ingredients and as an aid to initiating their reaction, an inert abrasive, such as ground glass. The essential reaction is the combustion of the fuel by the oxidizer, and all ingredients other than the fuel and the oxidizer may be regarded as combustion promoters.

The novel compound utilized in the priming mixtures contemplated by this invention is frictionand percussionsensitive, and is deficient in oxygen, so that it is capable of serving the dual purpose of either or both combustion initiator and fuel. Moreover, it decomposes under impact at such a rate and with such energy that it is capable of functioning as the sole explosive ingredient. Said compound is a complex or double iron salt of styphnic acid and hypophosphorous acid, apparently containing ferric styphnate and ferric hypophosphite in the proportions of 1-to-4. Its composition, manufacture and properties are more fully described in my prior patent above identified.

The said compound may be used in conjunction with very numerous combinations of known oxidizers and/or fuels and/or explosives. Typical ammunition priming compositions in which ferric styphnate-ferric hypophosphite functions as a percussion-sensitive ingredient, replacing such a material as tetrazene, are as follows:

if atent The preferred mixture in the above table shows in a standard drop test with a 2-oz. weight an average sensitivity of 3.26" and a standard deviation of 1.56".

Conventional priming mixtures, particularly those of the non-corrosive type, almost invariably contain lead, mercury or other heavy metal compounds, such as the lead styphnate included in the compositions above-mentioned, the decomposition of which leaves toxic residues which are undesirable, particularly when fired indoors. The use of ferric styphnate-ferric hypophosphite has been found to enable the production of non-corrosive priming compositions which are entirely free of lead and other toxic compounds. The use of such priming compositions in cartridges containing lead-free projectiles enables the manufacture of complete cartridges which are non-toxic and thus safe and desirable for use in confined spaces, such as various types of indoor ranges. Typical priming compositions of this group are the following:

Range, Preferred,

pcrcent percent Ferric styphnate-Ferric Hypophosphite 2550 40 Barium Nitrate 20-40 25 Glass 2H0 35 Per cent Ferric styphnate-ferric hypophosphite 2 to 25 Normal lead styphnate 25 to 45 Barium nitrate 20 to 40 Glass 20 to 40 3. An ammunition priming composition consisting essentially of Per cent Ferric styphnate-ferric hypophosphite 4 Normal lead styphnate 38 Barium nitrate 25 Glass 33 4. An ammunition priming composition consisting essentlally of Per cent Ferric styphnate-ferric hypophosphite 25 to 50 Barium nitrate 20 to 40 Glass 20 to 40 5. An ammunition priming composition consisting essentially of Per cent Ferric styphnate-ferric hypophosphite 40 Barium nitr 25 Glass 35 No references cited. 

1. AN AMMUNITION PRIMING COMPOSITION COMPRISING AS ESSENTIAL INGREDIENTS 2% TO 50% FERRIC STYPHNATE-FERRIC HYPOPHOSPHITE AND 20% TO 65% BARIUM NITRATE, BALANCE COMBUSTION PROMOTER. 